Comparative SETI?

It is likely that, with efficient compression, alien radio data will be
indistiguishable from white noise. So, even if we can pick up the
radio communications, it is not likely that our current pattern-finding
algorithms will find much of a pattern at all. It will just look like
another star.

However, we can predict the general shape of the spectrum of a star by
it's temperature. If we know the amount of radio (or microwave, or
visible) light that a star *should* emit, why don't we just look for
anomalies in the blackbody curve? For instance, anybody looking at the
Sun would see a yellow-orange star with way too much energy in the
radio spectrum. Furthermore, there would probably be a slight, but
maybe detectable, circadian period to the intensity.

Perhaps the biggest advantage of this is that it is necessarily a
broadband approach -- instead of scanning for patterns at a thousand
very specific bands, it would allow for a full-spectrum view. Also, it
would be easy enough to adapt SETI@Home to search for blackbody
anomalies, and the mere act of pulling together full spectra on so many
stars would be much more useful than just having their signatures on
the Hydrogen line, which by definition they don't really have much of
anyway.

If nothing else, this would be a way to narrow down the field of
candidate stars significantly. Is this being done?

On Tue, 28 Dec 2004 14:52:46 -0800, Roga wrote:
It is likely that, with efficient compression, alien radio data will be
indistiguishable from white noise. So, even if we can pick up the
radio communications, it is not likely that our current pattern-finding
algorithms will find much of a pattern at all. It will just look like
another star.

That's a problem only if we're intercepting broadcasts that they
intend for their internal consumption, and in that case chances
are they'd use a more focussed beam than we'd be likely to see.
If instead they're interested in communicating with people they
will use a means that they think people will be able to identify.

I don't know the answer to your primary question.
--
Jim Gillogly